© Vladimir Kalanov,
website"Knowledge is power".

Earth... Such a sweet planet, dear to all humanity. How much do we know about her? Yes many. Is there much that we don’t know about her? So many, Furthermore what we know. Our planet reveals its secrets quite reluctantly. To a large extent, this is because the secrets of planet Earth, so to speak, are not only personal, but also cosmic secrets, secrets of the Universe.

As a cosmic body, the Earth is a planet revolving around the Sun along with other planets (Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto).

Basic parameters of planet Earth

The average distance from the Earth to the Sun is 149597870 km.
The average distance from the Earth to the Moon is 384,400 km.
The time of a complete revolution of the Earth around its axis (sidereal day) is 23 hours 56 minutes. 4.09 sec.
The period of revolution of the Earth around the Sun ( tropical year) - 365.25 days
The average speed of the Earth's orbit is 29.76 km/sec.
Weight 6,000,000,000,000 billion tons.

Dimensions of the globe (ellipsoid):

The semimajor axis (equatorial radius), a - 6378.2 km.
Semi-minor axis (polar radius), b - 6356.9 km.
Compression c=(a-c)/a - 1: 298.3
Average radius of the Earth, taken as a sphere - 6371.2 km.
The length of the meridian is 40008.6 km.
The length of the equator is 40075.7 km. (diameter of the equator - 12756 km.)
Earth's surface - 510,100,000 sq. km.
Average height land above ocean level - 875 m.
The average depth of the world's oceans is 3800 m.
Highest height land above ocean level - 8848 m (Mount Everest)
The greatest depth of the world ocean is 11022 m. (Mariana Trench)

Distribution of land and water on the globe

Surface globe	North hemisphere		Southern Hemisphere		Earth as a whole
	million sq. km	%	million sq. km	%	million sq. km	%
Land	100	39	49	19	149	29
Water	155	61	206	81	361	71
Total	255	100	255	100	510	100

*) Data taken from the Small Atlas of the World, Moscow publishing house, 1980.

From these data follows the long-accepted fact that the Earth is slightly compressed at the poles. However, there is evidence that the Earth has a melon-shaped shape, i.e. compressed along the equator so that vertical axis it is several tens of kilometers greater than along the equatorial axis. But this hypothesis of scientists from the Californian Institute of Technology We do not consider them and present them here solely for the information of exotic lovers.

What is the actual shape of the Earth according to modern ideas official science? From the given data (Small Atlas of the World) it follows that the Earth is a ball with deviations from the mathematical precise shape. One cannot dare to call the Earth an ellipsoid: the difference between the major and minor axes of the ellipsoid is too tiny for the size of the Earth. Therefore, in science, the shape of the Earth is called a geoid. This must be understood to mean that the Earth has the shape of the Earth.

True, for people who observe the objects and natural phenomena around them day after day and do not think about their essence, causes and, especially, origin, it makes absolutely no difference what shape planet Earth has. They do not see the stunning beauty and great wisdom of the world around them, they do not have questions about why everything is arranged on Earth this way, and there is no desire to learn anything about the planet on which they live. Their interests are limited to the circle of everyday everyday concerns. There are many such people, they are close to us. I want to say right away: our story is not for them. Our story is for those people who are interested in everything about the Earth: its origin and age, its beauty and wealth, its uniqueness as cosmic body and as the place of origin of life and our stay human civilization. Our story is for people who are not just interested, but deeply concerned about the future of the Earth, its ecology, its entire biosphere, and, therefore, the future of humanity.

Origin of the Earth

At the beginning of our story about the Earth and geospheres, it is necessary to say how the Earth came into being. The question of the origin of the Earth is very complex, because we are talking about the origin of the entire solar system and even the entire galaxy called the Milky Way. There are many scientific hypotheses and simple assumptions on this topic. Suffice it to mention the hypothesis of the so-called big bang. Let us immediately note that any single coherent theory of the origin of the Universe and solar system still doesn't exist. Various hypotheses, put forward by different scientific schools and individual scientists, often contradict each other. You can dwell, for example, on the following hypothesis of the origin of the Solar system and the Earth:

Formation of the Sun and planets of the solar system. and the planets formed about five billion years ago from a huge cosmic cloud of gas and dust (1). This cloud had a flattened, lenticular shape - the shape of a disk. Scientists believe that both this disk and the Sun were formed from the same rotating mass of interstellar gas - the protosolar nebula. The least studied early stage origin of the Solar System - the release of a protosolar nebula from a giant parent molecular cloud belonging to the Galaxy.

Under the influence gravitational forces attraction, the cloud began to shrink, and a rotating disk of substances formed, the main part of which collected in the center (2). The central core was shrinking, attracting more and more matter, and at some point, in its depths, under the influence of enormous compression pressure, nuclear reaction(3) - the star lit up, the Sun appeared. The rest of the matter clung into smaller formations of rocks and gas clumps - this is how the planets were formed. The solar system has accepted modern look (4).

On initial stage During its formation, the Sun was very hot, which caused the evaporation into space of a large part of the light volatile substances (mainly hydrogen and helium) that were located in the region where the Earth was formed. In other words, the protoplanetary nebula around the Sun was divided into two parts different in composition and temperature: the one closest to the Sun contained less lungs elements and was sufficiently saturated with heavy elements, in contrast to the more distant one, depleted in heavy elements and consisting mainly of light gases. In the more distant and colder regions of the future solar system, light substances could condense, forming under the influence of gravity giant gaseous planets - “gas giant planets”, such as and.

Under the influence of gravitational forces, the matter of the solar nebula also accumulated in the inner part of the nebula - the formation of the Earth and other planets took place here terrestrial group. But due to the enormous temperature, the matter was in a molten state; denser substances, such as iron, nickel and their compounds, rushed to the center of the planet, while lighter ones, for example, silicates of various metals, from which rocks were subsequently formed, remained on the surface. This process is called gravitational differentiation. At the end of this process, the temperature on Earth gradually dropped so much that the process of solidification began.

It should be noted that this scenario is only one of the theoretical scenarios for the formation of the Earth. For example, in the 40s of the 20th century, academician O.Yu. Schmidt put forward the now generally accepted hypothesis about the formation of the Earth and other planets from cold, solid preplanetary bodies - planetesimals. Planetesimal (from the English planet - planet and infinitesimal - infinitesimal) - a body that represents an intermediate stage in the formation of a planet from a protoplanetary gas-dust cloud. We will consider in more detail the main points of the theories of planet formation in separate chapter, dedicated to the origin of the solar system.

Dear visitors!

Your work is disabled JavaScript. Please enable scripts in your browser, and the full functionality of the site will open to you!

465 meters per second is the speed of rotation of the Earth at the equator. 33 islands cross the equator. But what is the Equator? The length of the earth's equator is 40,075.696 km. Not that much, if you think about it. The length of the earth at the equator is calculated quite simply. 40,075 kilometers is the length of the equator. After conducting a series of complex experiments and calculations, he determined that the length of the Earth's equator was 252,000 stadia.

The equator divides the surface of the globe into North and Southern Hemisphere and serves as the starting point geographical latitude. Cities located at the latitude of the equator are Mbandaka (DRC), Mbarara (Uganda), Kisumu and Nakuru in Kenya, as well as the cities of Pontianak in Indonesia and Macapa in Brazil.

17 of them belong to Indonesia (two are in the lake on the island of Kalimantan), 9 are located at the mouth of the Amazon in South America, 5 - in the African Lake Victoria. For lack of written sources modern historians They cannot say with certainty what Neolithic man thought about the structure of the Earth.

And one of the ancient Indian texts reflected the theory according to which flat earth rests on three giant whales, and the whales swim in the ocean. This is an imaginary line that runs along the surface of the Earth in a plane passing through its center and perpendicular to the axis rotation of the planet. Passing through the Pillars of Hercules (Strait of Gibraltar), they entered the Atlantic Ocean, crossed the equator and circled Africa.

However, reaching the border between the Northern and Southern Hemispheres still did not make it possible to determine the length of the equator. Loud discoveries of new lands followed and sea ​​routes: America, waterway to India, Australia. Since Eratosthenes lived and worked in Alexandria, he used Egyptian stages.

Years and centuries passed. Improved measuring instruments and methods. Humanity went into space and was able to create detailed maps earth's surface. Now let’s try to answer the question of what is the reason for the discrepancy in the values ​​of the length of the equator between modern scientists and Eratosthenes. What if the equator simply became longer? It reacted with iron and nickel, which make up the Earth's core, resulting in the formation of hydrides of these elements.

Twice a year, on the days of autumn and spring equinox, the sun above it is at its zenith. IN Pacific Ocean The equator crosses Kiribati and the Baker Islands, which belong to the United States, then Ecuador, Colombia and Brazil, which are located on the South American continent.

The length of the equator was first calculated by ancient Greek scientist Eratosthenes, who was not only a great mathematician, geographer, poet, but also an astronomer. By measuring the time during which Sun rays reached the bottom of the well, the scientist was able to calculate the radius of the globe and find out what the length of the equator is.

What is the length of the Earth's equator?

To modern man It is very difficult to understand how a scientist, without any instruments, calculated the length of the equator, with an error of only 386 kilometers. In the 18th century, scientists from France were seriously engaged in such calculations. Literally, this means that the Earth has the shape of the Earth that is unique to it. Our planet seems to be flattened at the poles.

The circumference of the Earth at the equator is 40,000 km, but how many km will it be if measured through the poles?

It was thanks to the rotation that the bulge around the equator was formed. This is the name of the imaginary line that divides the Earth into two hemispheres - northern and southern, as if encircling it. The word comes from the Latin aequo, meaning “I make equal.”

By the way, day and night at the equator always last the same! With modern speeds and means of transportation, each of us has probably circled the earth more than once (just look at the readings of car instruments). The ancient Greek scientist Eratosthenes was able to calculate the length of the equator. Based on the premise that the Earth is spherical and the circumference is 360 degrees, we find the distance (chord) between two points located at a distance of a degree and multiply by 360. Simple?

Scientists calculated the length of the equator using the formula 2πR, despite the fact that the Earth is not spherical, but elongated in the form of an ellipse (a ball flattened at the poles). Many mathematicians and astronomers subsequently also tried to calculate the length of the equator. The Russians also did not stand aside and made their contribution to science, which made it possible to determine the length of the earth along the equator.

Poles (northernmost and most southern point planets). The equator also divides the Earth into the Southern Hemisphere and is an important line for navigational purposes, since its latitude is 0°, and all other measurements of parallels north or south to the poles are made from it.

Since the latitude of the Earth's equator is 0°, it is an important feature on the Earth's surface for navigation and exploration, as it serves as a starting point for studying the features of our planet based on latitude. For reference, the line of longitude corresponding to the equator is the Greenwich (prime) meridian.

Geography of the Earth's equator

The equator is the only line on the surface of the Earth, which is considered a great circle. Big circle- any circle drawn on a sphere (or spheroid, like the Earth) with a center that includes the center of that sphere. Thus, the equator is considered a great circle because it passes through the center of the Earth and bisects it. The other lines of latitude (parallels) north and south of the equator are not great circles because they narrow as they approach the poles and are not centered on the Earth.

The parallels are also large circles Earth, but due to the oblate shape of the planet, their circumference is less than at the equator.

Because our planet is an ellipsoid, slightly oblate at the poles and convex at the equator as a result of gravity and rotation, its diameter at the equator is 42.7 km (26.5 mi) greater than its polar diameter of 12,713.5 km (7,899.8 miles). Like diameter, the circumference of the Earth is also slightly larger at the equator due to the equatorial bulge. For example, at the poles the circumference is 40,008 km (24,859.82 miles), and at the equator it is 40,075.16 km (24,901.55 miles).

Moreover, since the Earth is an oblate ellipsoid, linear speed its rotation at the equator is greater than anywhere else. This is because the planet's circumference at the equator is approximately 40,000 km or 24,000 miles (for simplicity), and in 24 hours the Earth makes one full turn around its axis. Therefore, to find the linear speed of the Earth's rotation, divide 40,000 km (24,000 miles) by 24 hours to get 1,670 km (1,000 miles) per hour. When moving north or south from the equator, the Earth's circumference becomes smaller and, thus, the linear speed of rotation also decreases.

Climate and equator

Equatorial climate zone on the world map

The equator differs from the rest of the globe as physical environment, and geographical purpose. However, the biggest of these differences is its climate. The equator experiences the same climate patterns all year round, among which warm, humid or warm and dry conditions dominate climatic conditions. Most of The equatorial region is also characterized by high humidity. These climatic features due to the fact that the equator receives the highest level of solar radiation.

Countries along the equator

In addition to thick tropical forests, the equator line crosses the land and waters of 13 countries. Some of these countries are sparsely populated, but others, such as Ecuador, have high populations and some of their largest cities at the equator. For example, Quito, the capital of Ecuador, is within 1 km of the Equator, and in the center of this city there is a museum and monument marking it.

In addition to Ecuador, the equator line passes through the territories of the following countries: Republic of the Congo, Democratic Republic Congo, Sao Tome and Principe (by sea near the island of Rolash), Gabon, Uganda, Kenya, Somalia, Maldives (by sea between Suvadiva and Addu atolls), Indonesia, Kiribati (by sea), Colombia and Brazil.

Now you know that in the fabulous Universe of our distant ancestors, the Earth did not even resemble a ball. Residents Ancient Babylon imagined it as an island in the ocean. The Egyptians saw it as a valley stretched from north to south, with Egypt in the center. And the ancient Chinese at one time depicted the Earth as a rectangle... You smile, imagining such an Earth, but have you often thought about how people guessed that the Earth is not a limitless plane or a disk floating in the ocean? When I asked the guys about this, some said that people learned about the sphericity of the Earth after the first world travels, while others recalled that when a ship appears over the horizon, we first see the masts, and then the deck. Do these and some similar examples prove that the Earth is a sphere? Hardly. After all, you can drive around... a suitcase, and the upper parts of the ship would appear even if the Earth had the shape of a hemisphere or looked like, say,... a log. Think about this and try to depict what was said in your drawings. Then you will understand: the examples given only indicate that The earth is isolated in space and possibly spherical.

How did you know that the Earth is a ball? Helped, as I already told you, the Moon, or rather - lunar eclipses, during which the round shadow of the Earth is always visible on the Moon. Set up a small “shadow theater”: illuminate objects in a dark room different shapes(triangle, plate, potato, ball, etc.) and notice what shadow they create on the screen or just on the wall. Make sure that only the ball always forms a circle shadow on the screen. So, the Moon helped people learn that the Earth is a ball. To this conclusion, scientists in Ancient Greece(for example, the great Aristotle) ​​came back in the 4th century BC. But it's still a long time" common sense"man could not come to terms with the fact that people live on the ball. They could not even imagine how it was possible to live on the “other side” of the ball, because the “antipodes” located there would have to walk upside down all the time... But no matter where there was a person on the globe, everywhere a stone thrown upward will fall down under the influence of the Earth's gravity, that is, to the earth's surface, and if it were possible, then to the center of the Earth. In fact, people, of course, nowhere except circuses and gyms, you don’t have to walk upside down and head down. They walk normally anywhere on Earth: earth's surface under their feet, and the sky above their heads.

Around 250 BC, Greek scientist Eratosthenes for the first time measured the globe quite accurately. Eratosthenes lived in Egypt in the city of Alexandria. He guessed to compare the height of the Sun (or its angular distance from a point above your head, zenith, which is called - zenith distance) at the same point in time in two cities - Alexandria (in northern Egypt) and Siena (now Aswan, in southern Egypt). Eratosthenes knew that on the day of the summer solstice (June 22) the Sun was at noon illuminates the bottom of deep wells. Therefore, at this time the Sun is at its zenith. But in Alexandria at this moment the Sun is not at its zenith, but is 7.2° away from it. Eratosthenes obtained this result by changing the zenith distance of the Sun using his simple goniometric instrument - the scaphis. This is simply a vertical pole - a gnomon, fixed at the bottom of a bowl (hemisphere). The skafis is installed so that the gnomon takes a strictly vertical position (directed to the zenith). A pole illuminated by the sun casts a shadow divided into degrees inner surface skafisa. So at noon on June 22 in Siena the gnomon does not cast a shadow (the Sun is at its zenith, its zenith distance is 0°), and in Alexandria the shadow from the gnomon, as can be seen on the scaphis scale, marked a division of 7.2°. In the time of Eratosthenes, the distance from Alexandria to Syene was considered to be 5,000 Greek stadia (approximately 800 km). Knowing all this, Eratosthenes compared an arc of 7.2° with the entire circle of 360° degrees, and a distance of 5000 stadia with the entire circumference of the globe (let's denote it by the letter X) in kilometers. Then from the proportion

it turned out that X = 250,000 stadia, or approximately 40,000 km (imagine, this is true!).

If you know that the circumference of a circle is 2πR, where R is the radius of the circle (and π ~ 3.14), knowing the circumference of the globe, it is easy to find its radius (R):

It is remarkable that Eratosthenes was able to measure the Earth very accurately (after all, today it is believed that the average radius of the Earth 6371 km!).

But why is it mentioned here? average radius of the Earth, Aren't all the radii of a ball the same? The fact is that the figure of the Earth is different from the ball. Scientists began to guess about this back in the 18th century, but it was difficult to find out what the Earth really was like - whether it was compressed at the poles or at the equator. To figure this out, French Academy Sciences had to equip two expeditions. In 1735, one of them went to carry out astronomical and geodetic work in Peru and did this in the equatorial region of the Earth for about 10 years, and the other, Lapland, worked in 1736-1737 near the Northern Arctic Circle. As a result, it turned out that the arc length of one degree of the meridian is not the same at the Earth's poles and at its equator. The meridian degree turned out to be longer at the equator than at high latitudes (111.9 km and 110.6 km). This can only happen if the Earth is compressed at the poles and is not a ball, but a body similar in shape to spheroid. At the spheroid polar radius is smaller equatorial(the polar radius of the earth's spheroid is almost shorter than the equatorial radius 21 km).

It's good to know that great Isaac Newton (1643-1727) anticipated the results of the expeditions: he correctly concluded that the Earth is compressed, which is why our planet rotates around its axis. In general, the faster a planet rotates, the greater its compression should be. Therefore, for example, the compression of Jupiter is greater than that of the Earth (Jupiter manages to rotate around its axis in relation to the stars in 9 hours 50 minutes, and the Earth only in 23 hours 56 minutes).

And further. The true figure of the Earth is very complex and differs not only from a sphere, but also from a spheroid rotation. True, in in this case we're talking about about the difference not in kilometers, but... meters! Scientists are still engaged in such a thorough clarification of the figure of the Earth, using for this purpose specially conducted observations with artificial satellites Earth. So it is quite possible that someday you will have to take part in solving the problem that Eratosthenes took on a long time ago. This is very what people need case.

What is the best figure for you to remember on our planet? I think that for now it is enough if you imagine the Earth in the form of a ball with an “additional belt” put on it, a kind of “splash” on the equator region. Such a distortion of the Earth’s figure, turning it from a sphere into a spheroid, has considerable consequences. In particular, due to the attraction of the “additional belt” by the Moon, the earth’s axis describes a cone in space in about 26,000 years. This is the movement earth's axis called precessional. As a result, the role North Star, which now belongs to α Ursa Minor, is alternately played by some other stars (in the future it will become, for example, α Lyrae - Vega). Moreover, due to this ( precessional) movement of the earth's axis Zodiac signs more and more do not coincide with the corresponding constellations. In other words, 2000 years after the Ptolemaic era, the “sign of Cancer,” for example, no longer coincides with the “constellation Cancer,” etc. However, modern astrologers try not to pay attention to this...

In two halves. In this regard, it is not surprising that people wonder: what is the equator? The equator is conditional line, which exactly intersects the surface of our Earth with a plane that is considered perpendicular to the axis of rotation of the planet and passes directly through its center. From Latin the word “aequator” is translated as “equalizer.” This line is a conditional beginning for measuring geographic latitude, which is equal to 0 degrees at the equator.

The length of the equator is 40,075.676 km, the remaining lines (parallels) are always less than its length. Throughout his lineage, day is constantly equal to night. It is the equator that divides our planet into two hemispheres, Southern and Northern. Twice a year, on the days of the autumn and spring equinox, the sun is at its zenith above it. falls on March 20-21, and autumn - on September 23. These are located directly above your head, and objects do not cast shadows.

Scientists calculated the length of the equator using the formula 2πR, despite the fact that the Earth is not spherical, but elongated in the form of an ellipse (a ball flattened at the poles). However, the radius of our planet is conventionally taken to be the radius of the ball. The length of the earth at the equator is long line circling the Earth. Interesting fact is that it crosses 14 states.

If you move from towards the east, the equator crosses states such as Sao Tome and Principe in Atlantic Ocean, then Gabon, Congo, Kenya, Uganda, Somalia in Africa. Moving on Indian Ocean, it passes through the Maldives and Indonesia. In the Pacific Ocean, the equator crosses Kiribati and the Baker Islands, which belong to the United States, then Ecuador, Colombia and Brazil, which are located on the South American continent. These countries are the hottest on the planet.

The length of the equator was first calculated by the ancient Greek scientist Eratosthenes, who was not only a great mathematician, geographer, poet, but also an astronomer. By measuring the time during which the sun's rays reached the bottom of the well, the scientist was able to calculate the radius of the globe and find out how long the equator is. These calculations are very approximate, but they gave much to subsequent generations of scientists to more accurately calculate the length of this imaginary line. Eratosthenes of Cyrene was born in 276 BC. and died in 194 BC.

He was one of the greatest scientists ancient world. He was born in the Greek city of Cyrene and at the invitation of the king Ptolemy III Evergeta was in charge Library of Alexandria. This great scientist died of hunger, in terrible poverty, but went down in history as an insightful researcher with an extraordinary approach to science. The length of the equator according to Eratosthenes was 252 thousand stadia, which is 39,690 km. Creator of mathematical and physical geography Eratosthenes made great discoveries in many fields. It is very difficult for a modern person to understand how a scientist, without any instruments, calculated the length of the equator, with an error of only 386 kilometers.

Many mathematicians and astronomers subsequently also tried to calculate the length of the equator. Dutchman Snell in early XVII century proposed to calculate this value without taking into account the obstacles encountered. In the 18th century, scientists from France were seriously engaged in such calculations. The Russians also did not stand aside and made their contribution to science, which made it possible to determine the length of the earth along the equator. Director V.Ya. Struve carried out these measurements in degrees from 1822 to 1852, and in 1941 the Soviet geodesist F.N. Krasovsky was able to calculate the length of the earth's ellipse, which is the starting point for modern scientists around the world, since it is recognized as the standard.